CN106590610B

CN106590610B - Water-based fracturing fluid drag reducer and application thereof

Info

Publication number: CN106590610B
Application number: CN201510683795.5A
Authority: CN
Inventors: 喻德峰; 沈之芹; 翟晓东; 沈少春; 李慧琴; 王辉辉; 沙鸥; 李应成
Original assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Current assignee: China Petroleum and Chemical Corp; Sinopec Shanghai Research Institute of Petrochemical Technology
Priority date: 2015-10-20
Filing date: 2015-10-20
Publication date: 2022-04-01
Anticipated expiration: 2035-10-20
Also published as: CN106590610A

Abstract

The invention relates to a novel water-based fracturing fluid drag reducer composition and application of the composition as a fracturing fluid drag reducer, and mainly solves the problems of low drag reduction rate and low tolerance to hard water of a surfactant drag reducer in the prior art; the long-chain fatty acid salt is selected from at least one of a formula (II), a formula (III) or a formula (IV); the technical scheme that the weight ratio of the cationic surfactant to the long-chain fatty acid salt is 50: 1-1: 50 well solves the technical problem, and can be used in the shale air pressure fracturing mining process.

R₄COOM formula (II); r₄SO₃M is formula (III); r₄SO₄M is represented by the formula (IV).

Description

Water-based fracturing fluid drag reducer and application thereof

Technical Field

The invention relates to a water-based fracturing fluid drag reducer and a preparation method and application thereof.

Background

Shale gas reservoirs generally belong to ultra-low-porosity and low-permeability reservoirs, the permeability of the shale gas reservoirs is 2-3 orders of magnitude lower than that of compact clastic rock gas reservoirs, and fracturing modification is an important means for exploration and development aiming at the gas reservoirs. The fracturing technology suitable for exploiting the low-permeability and low-porosity unconventional reservoir stratum is increasingly applied to shale gas reservoir exploitation. However, the injected water is hindered by the flow shear stresses in the pipe and rock strata and the fluid displacement is greatly reduced. Effectively reduce the friction of liquid and hinder can reduce the demand to equipment, reduce construction cost to a certain extent. Therefore, to reduce friction, slickwater fracturing fluids typically require the addition of drag reducing agent additives.

The earliest water-based drag reducers were polymers, but the solution polymer products themselves were highly viscous, low in polymer content, long in dissolution time, and chemically unstable, thus providing great invariance to shipping and use. Most importantly, polymer drag reducers are generally linear molecules with molecular weights greater than 50 ten thousand, but under the action of strong shearing force, high temperature and other factors, long-chain structures are damaged and cannot be repaired. Therefore, surfactant drag reducers capable of forming worm-like micelles have attracted considerable attention. And the surfactant can effectively reduce the contact angle and the surface tension between the injected fluid and reservoir fluid and rock, reduce the capillary force of drag reduction water flowing in the shale reservoir, and further improve the fracturing effect.

Surfactant wormlike micelles at low Reynolds number (less than 10)⁴) Present in the aqueous solution in a disordered array, has little effect on flow shear. At high Reynolds number (greater than 10)⁴) The directional arrangement of the micelles results in a very pronounced drag reducing effect. At higher reynolds numbers (greater than 10)⁵) The high shear stress destroys the wormlike micelles, and the drag reduction effect is rapidly reduced. The range of reynolds coefficients over which the surfactant system has significant drag reducing effect depends on many factors, such as: total concentration, formulation, surfactant hydrophobic chain length, and the like.

A large body of literature indicates that mixed systems of cationic surfactants and organic salts are prone to form worm-like micelles. Some of these systems are effective for use in heat exchange applications in pipelines (U.S. patent No. 4705860, entitled, quaternary ammonium salts and the use as drain reduction agents), but most cationic surfactant/organic salt systems, such as the cetyl trimethylammonium bromide/sodium salicylate system, tend to change from worm-like to spherical micelles at high reynolds numbers, lose drag reducing properties, and precipitate out in high calcium magnesium aqueous systems. In order to obtain surfactant drag reducing agent formulations with better drag reduction performance at high reynolds numbers and higher hard water tolerance, we have sought novel combinations of amphoteric surfactants and long chain fatty acid salts. I find that the surfactant formula of the type can effectively improve the tolerance to hard water and obtain good resistance reduction effect.

Disclosure of Invention

One of the technical problems to be solved by the invention is the problems of low drag reduction rate and low tolerance to hard water of a surfactant drag reducer in the prior art, and provides a novel drag reducer for a water-based fracturing fluid, which has the advantages of high drag reduction rate and strong tolerance to hard water when used in the water-based fracturing fluid.

The invention also provides an application of the water-based fracturing fluid drag reducer in fracturing fluid.

In order to solve one of the above technical problems, the technical solution of the present invention is as follows: a water-based fracturing fluid drag reducer composition comprising an amphoteric surfactant of formula (I) and a long chain fatty acid salt; the long-chain fatty acid salt is selected from at least one of fatty acid salts shown in a formula (II), a formula (III) or a formula (IV); wherein R is a saturated or unsaturated aliphatic group or acyl group having 8 to 24 carbon atoms₁And R₂Independently selected from alkyl of 1 to 4 carbon atoms or hydroxyalkyl of 2 to 4 carbon atoms, R₃Is an alkylene group having 1 to 6 carbon atoms;

wherein the weight ratio of the amphoteric surfactant to the long-chain fatty acid salt is 1 (0.02-50); the long-chain fatty acid salt is selected from at least one of fatty carboxylate, fatty sulfonate or fatty sulfate.

In the above technical scheme, R₁And R₂Preferably methyl, ethyl or propyl.

In the above technical scheme, R₃Preferably an alkylene group having 2 to 3 carbon atoms.

In the above-mentioned embodiments, R is preferably an aliphatic group or R₅NHC₃H₆-, wherein R₅Is an acyl group.

In the technical scheme, the long-chain fatty acid salt is preferably at least one of fatty acid salts shown in a formula (II), a formula (III) or a formula (IV);

R₄COOM formula (II); r₄SO₃M is formula (III); r₄SO₄M is formula (IV);

wherein R is₄Preferably a saturated or unsaturated aliphatic group having 8 to 24 carbon atoms, M is independently preferably H, an alkali metal or NH₄；

In the technical scheme, the long-chain fatty acid salt preferably contains a saturated or unsaturated aliphatic group with 12-22 carbon atoms.

In the above technical solution, the optimal technical solution is: a water-based fracturing fluid drag reducer comprising the amphoteric surfactant of formula (I) and the long-chain fatty acid salt; the long-chain fatty acid salt is selected from at least one of fatty acid salts shown in a formula (II), a formula (III) or a formula (IV); wherein R is a saturated or unsaturated aliphatic group having 8 to 24 carbon atoms, more preferably an aliphatic hydrocarbon group having 12 to 22 carbon atoms, and still more preferably an alkyl or alkenyl group having 12 to 24 carbon atoms; r₁And R₂Independently selected from alkyl of 1 to 4 carbon atoms or hydroxyalkyl of 2 to 4 carbon atoms, R₃Is an alkylene group having 1 to 6 carbon atoms, and more preferably an alkylene group having 2 to 3 carbon atoms; r₄Is a saturated or unsaturated aliphatic group having 8 to 24 carbon atoms, more preferably a saturated or unsaturated aliphatic hydrocarbon group having 12 to 22 carbon atoms, and further preferably an alkyl or alkenyl group having 12 to 22 carbon atoms; m is selected from H, alkali metal or NH₄. The highest drag reduction can be maintained above 65% and the degree of mineralization of water can be tolerated as 11786 ppmw.

In the above technical solution, as a preferable solution: preferably, at least two of the amphoteric surfactants shown in the formula (I) are compounded with one of the fatty carboxylate, the fatty sulfonate or the fatty sulfate, so that a better synergistic effect can be achieved, and the drag reduction effect of the compound is obviously better than the effect of compounding one of the amphoteric surfactants shown in the formula (I) with one of the fatty carboxylate, the fatty sulfonate or the fatty sulfate.

In the above technical solution, as a preferable solution: preferably, one of the amphoteric surfactants shown in the formula (I) is compounded with at least two of the fatty carboxylate, the fatty sulfonate or the fatty sulfate, so that a better synergistic effect can be achieved, and the drag reduction effect of the compound is also obviously better than the effect of compounding one of the amphoteric surfactants shown in the formula (I) with one of the fatty carboxylate, the fatty sulfonate or the fatty sulfate.

In the technical scheme, the water-based fracturing fluid drag reducer can also comprise water, wherein the mass volume concentration of the amphoteric surfactant and the long-chain fatty acid salt is preferably 0.1-10 kg/m³。

The fracturing fluid drag reducer can be supplied in a solid form for storage and transportation, and can be added into the fracturing fluid on site for use; or can be uniformly mixed and then supplied in the form of solid mixture and added into the fracturing fluid on site for use; it can also be supplied in the form of an aqueous solution for on-site use. The compositions of the present invention may also include other components commonly used in the art, such as clay stabilizers, biocides, scale inhibitors, pH adjusters, fluid loss additives, demulsifiers, and the like.

When the invention adopts the form of aqueous solution, the invention can adopt the form of concentrated solution, and the concentrated solution can be diluted when in use or preferably directly prepared into the concentration for field use, and the concentration for field use preferably accounts for 0.1-10 kg/m of the fracturing fluid by the total amount of the amphoteric surfactant and the long-chain fatty acid salt³。

In order to solve the second technical problem, the technical scheme of the invention is as follows: the application of the water-based fracturing fluid drag reducer in the technical scheme of one of the technical problems in the fracturing fluid.

In the above technical scheme, the preferable scheme is: the fracturing fluid is preferably a water-based fracturing fluid; the application temperature is preferably 5-120 ℃; the concentration of the amphoteric surfactant and the long-chain fatty acid salt in the fracturing fluid is preferably 0.1-10 kg/m³The long-chain fatty acid salt is preferably the long-chain fatty acid salt described above.

The fracturing fluid drag reducer is used in fracturing fluid, has no special requirement on the water quality of the fracturing fluid, and can ensure that deionized water, clean water, river water, sewage, mineralization water, formation water and the like which are well known by a person skilled in the art can be used.

The determination method of the resistance reduction rate of the composition of the invention is as follows:

the drag reduction ratio of the fracturing fluid drag reducer is obtained by testing the flow loop friction resistance testing system. Experimental testing the water-based solution was tested for pressure differential changes with flow rate in a 3 meter stainless steel round tube having an inner diameter of 1/2 inches. When the turbulence drag reduction flow research is carried out, after the change result of the fanning friction coefficient of the turbulence drag reduction flow along with the Reynolds number is measured, the fanning friction coefficient of water under the same Reynolds number is compared to obtain the drag reduction rate. The drag reduction ratio DR is obtained from the pressure difference data as follows:

in the formula: Δ P is the pressure differential, KPa, of the formulated drag reducing agent fluid as it passes through the test line;

ΔP_sis the pressure difference, KPa, when the clean water passes through the test pipeline.

The reynolds number Re is defined by the parameters of the flowing fluid:

mu is the viscosity of the solvent, rho is the density of the fluid, Q is the flow rate of the fluid, and D is the inner diameter of the pipeline, so the Reynolds number is in direct proportion to the flow rate. The final data obtained is the relation curve between the drag reduction ratio DR and the Reynolds coefficient.

The drag reduction rate of the water-based fracturing fluid drag reducer is determined by taking the drag reduction rate when the fixed Reynolds coefficient Re is 20000.

The technical key point of the invention is to form a novel fracturing fluid drag reducer formula, the combination of an amphoteric surfactant and a long-chain fatty salt is utilized to prepare the high-efficiency fracturing fluid drag reducer, and the water-based fracturing fluid drag reducer is used in the fracturing fluid, especially the water-based fracturing fluid, and the use temperature is 5-120 ℃, and the use concentration is 0.1-10 kg/m³Under the condition, the resistance reducing rate can reach 80 percent, the mineralization degree of water can be tolerated to be higher than 10000ppmw, and a better technical effect is obtained.

The invention is described in detail below with reference to the drawings and the detailed description.

Drawings

FIG. 1 is a graph of drag reduction ratio DR versus Reynolds number.

Detailed Description

The following examples used water having a degree of mineralization of 11786ppmw, with 72.6ppmw calcium ions, 2.5ppmw magnesium ions, 4019.5ppmw sodium ions, and 4332.5ppmw chloride ions.

[ COMPARATIVE EXAMPLE 1 ]

N-dodecyl betaine, sodium dodecyl diphenyl ether disulfonate and the like are compounded in mass, and dissolved in hard water to prepare 2000ppmw of drag reducer aqueous solution, and the drag reduction rate is tested at different temperatures without the drag reduction rate.

[ COMPARATIVE EXAMPLE 2 ]

The oleamidobetaine, the sodium oleate and the like are compounded in mass and dissolved in hard water to prepare 1000ppmw of drag reducer aqueous solution without drag reduction rate.

[ COMPARATIVE EXAMPLE 3 ]

Cetyl trimethyl ammonium bromide and sodium salicylate are mixed by mass, dissolved in deionized water to prepare 2000ppmw of resistance reducing agent aqueous solution, and precipitated at the temperature of 15 ℃. The drag reduction rate at different temperatures is tested, and the highest drag reduction rate can be kept at 65%. The temperature application range is 20-60 ℃.

[ COMPARATIVE EXAMPLE 4 ]

Cetyl trimethyl ammonium bromide and sodium salicylate are compounded by mass, dissolved in hard water to prepare 1000ppmw of resistance reducing agent aqueous solution, and precipitated.

[ example 1 ]

The N-dodecyl betaine, the sodium stearate and the like are compounded by mass and added into hard water to prepare 1000ppmw of aqueous solution, and the drag reduction rate at different temperatures is tested, wherein the highest drag reduction rate can be kept at 60%. The temperature application range is 30-100 ℃.

[ example 2 ]

The mass of N-dodecyl betaine, sodium oleate and the like are compounded and added into hard water to prepare 1000ppmw aqueous solution, and the drag reduction rate at different temperatures is tested, wherein the highest drag reduction rate can be kept at 70 percent, as shown in figure 1. The temperature application range is 5-100 ℃.

[ example 3 ]

And (3) compounding the N-dodecyl betaine, the sodium erucate and the like in mass, adding the mixture into hard water to prepare 1000ppmw of aqueous solution, and testing the drag reduction rate at different temperatures, wherein the highest drag reduction rate can be kept at 70%. The temperature application range is 5-120 ℃.

[ example 4 ]

And (3) compounding N-dodecyl betaine, sodium palmitate and the like in mass, adding the mixture into hard water to prepare 1000ppmw of aqueous solution, and testing the drag reduction rate at different temperatures, wherein the highest drag reduction rate can be kept at 65%. The temperature application range is 20-90 ℃.

[ example 5 ]

And (3) compounding N-dodecyl betaine, sodium laurate and the like in mass, adding the mixture into hard water to prepare 1000ppmw of aqueous solution, and testing the drag reduction rate at different temperatures, wherein the highest drag reduction rate can be kept at 65%. The temperature application range is 5-60 ℃.

[ example 6 ]

The N-dodecyl betaine, the sodium dodecyl sulfate and the like are compounded by mass and added into hard water to prepare 1000ppmw of aqueous solution, and the drag reduction rate at different temperatures is tested, wherein the highest drag reduction rate can be kept at 50%. The temperature application range is 5-50 ℃.

[ example 7 ]

And (3) compounding N-dodecyl betaine, sodium dodecyl sulfate and the like by mass, adding the mixture into hard water to prepare 1000ppmw of aqueous solution, and testing the drag reduction rate at different temperatures, wherein the highest drag reduction rate can be kept at 50%. The temperature application range is 5-50 ℃.

[ example 8 ]

And (2) compounding N-tetradecyl betaine, sodium oleate and the like in mass, adding the mixture into hard water to prepare 1000ppmw of aqueous solution, and testing the drag reduction rate at different temperatures, wherein the highest drag reduction rate can be kept at 50%. The temperature application range is 10-100 ℃.

[ example 9 ]

And compounding N-hexadecyl betaine, sodium oleate and the like in mass, adding the mixture into hard water to prepare 1000ppmw aqueous solution, and testing the drag reduction rate at different temperatures, wherein the highest drag reduction rate can be kept at 50%. The temperature application range is 10-110 ℃.

[ example 10 ]

N-hexadecyl betaine, sodium docosanoate and the like are compounded by mass, and are added into hard water to prepare 1000ppmw of aqueous solution, and resistance reduction rates at different temperatures are tested, wherein the highest resistance reduction rate can be kept at 50%. The temperature application range is 65-110 ℃.

[ example 11 ]

N-hexadecyl betaine and N-dodecyl betaine are mixed according to a molar ratio of 1: 1 mixing to obtain a betaine compound, then compounding the betaine compound with sodium oleate and the like by mass, adding the mixture into hard water to prepare 1000ppmw aqueous solution, and testing the drag reduction rate at different temperatures, wherein the highest drag reduction rate can be kept at 80%. The temperature application range is 5-110 ℃. (has better synergistic effect and obviously better effect than the embodiments 2 and 9)

[ example 12 ]

Sodium docosanoate and sodium oleate are added according to a molar ratio of 1: 1, mixing to obtain a composite fatty acid salt, then compounding the composite fatty acid salt with N-hexadecyl betaine and the like by mass, adding the mixture into hard water to prepare 1000ppmw of aqueous solution, and testing the drag reduction rate at different temperatures, wherein the highest drag reduction rate can be kept at 76%. The temperature application range is 10-110 ℃. (has better synergistic effect and obviously better effect than the examples 9 and 10)

The inventors of the present invention found that the chain length and the degree of unsaturation of the long-chain fatty acid salt according to the present invention directly affect the applicable temperature range, and the longer the chain length, the higher the upper temperature limit, the higher the degree of unsaturation, and the lower temperature limit. This can also be seen visually in the same ratios as in examples 1 to 5. The inventor of the invention also finds that in a mixed system of the betaine surfactant and the fatty acid salt, when the betaine is amido betaine, the drag reduction effect is poor.

TABLE 1

Claims

1. A water-based fracturing fluid drag reducer, comprising at least two of the amphoteric surfactants of formula (I) and one of long-chain fatty acid salts; or comprises one of the amphoteric surfactants shown in the formula (I) and at least two of long-chain fatty acid salts;

wherein R is an alkyl or alkenyl group having 12 to 24 carbon atoms, R is₁、R₂Independently selected from alkyl of 1 to 4 carbon atoms or hydroxyalkyl of 2 to 4 carbon atoms, R₃Is an alkylene group having 1 to 6 carbon atoms;

wherein the weight ratio of the amphoteric surfactant to the long-chain fatty acid salt is 1 (0.02-50); the long-chain fatty acid salt is selected from fatty carboxylic acid salts shown in a formula (II):

R₄COOM formula (II);

wherein R is₄Is alkyl or alkenyl containing 12-22 carbon atoms, M is independently selected from H, alkali metal or NH₄。

2. The water-based fracturing fluid drag reducer of claim 1, wherein R is₁And R₂Is methyl, ethyl or propyl.

3. The water-based fracturing fluid drag reducer of claim 1, wherein R is₃Is methylene.

4. Use of the aqueous-based fracturing fluid drag reducer of any of claims 1 to 3 in a fracturing fluid.

5. The use of the water-based fracturing fluid drag reducer of claim 4, wherein the fracturing fluid comprises water, and wherein the amphoteric surfactant and the long-chain fatty acid salt are present in the fracturing fluid at a concentration of 0.1-10 kg/m in total³。

6. The use of the water-based fracturing fluid drag reducer of claim 4 in a fracturing fluid, wherein the temperature of the use is 5-120 ℃.